This invention relates to an apparatus for reinforcing extruded elastomeric or plastic tubing.
Devices for manufacturing reinforced tubing by helically winding two sets of filaments around the tubing in opposite directions are well known in the art (Teichman U.S. Pat. No. 2,800,683, Klein U.S. Pat. No. 3,375,550). In both of these devices the reinforcing filament is fed through one or more holes in the nozzle. The portion of the nozzle through which the reinforcing filament passes is part of the spool carriers which rotate.
In the present invention the reinforcing filaments are fed to the surface of the molten or softened tubing through an annular slot or opening extending through the wall portion of the nozzle around the mandrel. The use of an annular opening is an improvement over the prior art in that it eliminates rotation of the nozzle or any portion thereof.